Electrical Engineering Stack Exchange
Electrical Engineering Stack Exchange

Questions tagged [watts]

The unit of measurement and SI unit for power, named after James Watt. It is equivalent to energy flow per second or joules/second. In electrical terms: $ P = I\cdot R = I^2 \cdot R = \frac{V^2}{R}$

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Why don't power meters measure volt-amps

When large inductive or capacitive loads are applied, the power meter will not indicate and bill you as the electricity gets lost in the lines. Why don't power companies just charge for this?
skyler
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Heater requirements to quickly heat a large aluminum sheet

I'm building a sublimation heat press. I have a 1000x250x8 mm sheet of cast aluminum. I will be using a thermostatically controlled silicon heat mat to regulate the heat up to a maximum 392 degrees Fahrenheit (200°C). I want to be able to reach my…
tonycarr
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What does the power rating of 10W mean?

When hair clippers or similar appliances are rated at, for example, 10W, does that mean 10W per hour or second? I'm trying to determine power of various hair clippers.
Damian
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Calculate wattage of incandescent bulb

I'm trying to find out the wattage of some bulbs supplied to a company I'm working for. The product is a set of garden lights (Cheap Chinese) which is 10x small bulbs in parallel, powered by a 12Vac 5A 60VA transformer. The issue is we seem to be…
Digital Lightcraft
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MWh for one day expressed in MW

I have read the other question on this topic, but having gone through the answer I'm still unsure about the answer to my own, so I hope this is helpful. If a generator generated 20MWh of electricity in a day (24 hours), then how would I express that…
user3469285
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How can I communicate the difference between 2 watts of continuous power and a 2 watt capacity?

I'm trying to understand the difference between a power output in watts and a power capacity in watts, and I'm open to the possibility that I'm thinking about it all wrong. If I want to charge a battery with a 2 watt-hour capacity, how long is it…
Scott Hillson
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Poor-Man's Power Meter

I would like to measure the power of a very unusual ac waveform. Please say if this could work... Construct a black pvc tube with a very sensitive light to voltage converter TSL257 in one end, and a tiny lamp in the other end, seal both…
William Mingin
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Convert kWh to watts per m²

I am from a computer science background, I need some help with some electrical engineering problem. Electricity consumption for a home in the last 56 days is 7561 kWh. There are two floors. The combined area is 300 square meters. Can I use this…
user1847624
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Electrical Power Question

I am trying to compare watts exiting the battery vs watts being consumed by the bulb. I have set up a test circuit shown below. Should not A-B watts match C-D watts?? Sorry for such a basic question...I'm learning here...
William Mingin
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What wattage should I use for a switching adapter?

I have a bad switching adapter. It has a DC output of 14.5V 2.48A Max. I can't find a match anywhere. I think a 3.0 Max will work, but I don't know the wattage. The replacements I've found are 29W, 45W and 60W. Does anyone know which one would work…
Trent
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Does a 5w LED lamp require 5w/per hour to run ?

Does a 5w LED lamp require 5w/per hour to run ? eg. would 200 x 5w LED lamps running for 1 hour would require 1kwhr of electricity. Or is the 5w related to some other time scale ?
user27511
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Will a man get electrocuted if he places the electrical test screwdriver on his foot?

Below is the typical circuit when somebody do the "test light" on wall electricity socket (Image 1): In this "images 1", very little current will flow into his body, because the high electrical resistance of the "Test Screwdriver", then the "Test…
Zynskav Zynskav
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Can I use low voltage but higher maximum amperage?

I have an electronic device (electromagnet solenoid) that working on 9V/DC and 30mA current (9*30=270mW) Question 1: If there is a 5V/DC adapter that could produce maximum 54mA (5*54=270mW), could I use it to power that solenoid? Question 2: Does…
Zynskav Zynskav
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kWh per 24hours from system that uses 950W

my friend asked me a questions how much kWh he would get per day around if he is going to buy a power suply that is 1200W and place in the system and system would use 950W as he said http://www.newegg.com/Product/Product.aspx?Item=N82E16817153145…
Driglou
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Is the watt value on the device, or appliance label in watts per seconds or kWh?

I know the label says watts on the device, but since units of watts and kWh are used interchangeably to solve for amperage and calculating energy usage, it's not clear to me, and I can't find a definitive answer here, or online. So, are the units in…
AlwaysLearning
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